Results of the deuteron trajectory reconstruction

in the PAMELA experimentKoldobskiy Sergey A.

National Research Nuclear University MEPhI, Moscow, Russia

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

PAMELA Experiment

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Deuteron analysis resultsResults of deuteron spectrum reconstruction for GCR and re-entrant albedo particles have been published already and can be found in the following works:Adriani, O., Barbarino, G.C., Bazilevskaya, G.A. et al., Astrophysical Journal, 2013, V.770 (1), p. 2.Koldobskiy, S., Adriani, O., Barbarino, G.C., et al., Bulletin of the Russian Academy of Sciences: Physics, 2015, V. 79 (3), pp. 294-297.

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Deuteron identificationThe deuteron identification procedure is based of multiparameter correlative analysis of signals from tracker and ToF system. Values of particle rigidity, velocity and multiple measurements of energy losses are used.The identification procedure was updated in comparison to the procedure used for deuteron spectrum reconstruction, because if we want to reconstruct trajectories we need to know that every considered into account event is a deuteron. So stricter cuts was used.Data sample from July 2006 to January 2008 was used and more than 82.000 deuteron events with energy from 100 to 400 MeV/nucleon were selected.

Rigidity, GV

ΔE

Deuterons

Protons

Num

ber o

f eve

nts

1/β

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Track reconstruction routineEach selected deuteron event was backtraced from the registration point.Track reconstruction was done on basis of known particle rigidity, point of registration, vector of particle motion by solving particle motion equations with numerical integration methods implementing International Geomagnetic Reference Field Model (IGRF) as internal geomagnetic field model. Trajectories were traced until:1. they reached the boundaries of Earth’s magnetosphere during backtracing; these particles were classified as GCR d;2. they intersected the boundaries of “dense” atmosphere, which was assumed at an altitude of 30 km; these particles were classified as re-entrant albedo deuterons;3. they survived more than 10 seconds and fulfill adiabatic conditions; these particles were classified as d of radiation belt.

x, ×1000 km

z, ×

1000

km

y, ×1000 km

Examples of reconstructed deuteron trajectories

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Coordinates of GCR d registration

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Re-entrant albedo ILifetime for albedo particles

So there is two types of re-entrant albedo deuterons:- short-lived;- long-lived.Short-lived d adsorbs quickly by atmosphere.

Example of long-lived d trajectory (9.8 sec livetime) generated in the East of SAA

lifetime >10 sec

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Re-entrant albedo II

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Re-entrant albedo II

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Radiation belt deuterons IThe typical trajectory of RB deuteron Rigidity composition for deuterons in RB

x, ×

1000

km

y, ×1000 km

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

85 – 140 MeV/n 140 – 215 MeV/n 215 – 300 MeV/n

Radiation belt deuterons II

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

ConclusionsTrajectory reconstruction was done for deuterons registered in PAMELA experiment with energies from 80 to 400 MeV/nucleon for a first time.Three populations of deuterons are clearly distinguished: GCR, albedo, trapped particles.Subpopulations of albedo deuterons are observed: short-lived splash, long-lived quasitrapped and psedotrapped (penumbra) particles.Results for deuterons are close to PAMELA results for protons (Geophys. Journal-Space 2015).

Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

Thank you for attention